Receiver tank for use in refrigeration cycle, heat exchanger with said receiver tank, and condensing apparatus for use in refrigeration cycle

ABSTRACT

A receiver-tank is provided with a vertical tank main body  140.  An inlet  131  and an outlet 132 are provided in an inlet-and-outlet forming member  150  as a bottom wall of the tank main body  140.  A desiccant-filled-layer  135  as a flow-resistance layer is provided in a lower part of the tank main body  140,  and an upper space is formed above the desiccant-filled-layer  135.  A suction pipe  133  is provided in the tank main body  140  with the lower end connected with the outlet  132  and the upper end opened toward the upper space. When the refrigerant introduced into the tank main body  140  from the inlet port  131  goes up through the desiccant-filled-layer  135,  the flow velocity decreases, and liquid-stagnation R is quietly created bin the upper space. The liquefied refrigerant of this liquid-stagnation R flows out of the outlet  132  through the suction pipe  133.  Thereby, the stable liquid refrigerant can be supplied.

[0001] This is a continuation-in-part of commonly assigned copendingapplication Ser. No. 09/716,397, filed Nov. 2, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to a receiver tank for use in arefrigeration cycle, a heat exchanger with a receiver tank, and acondensing apparatus for use in a refrigeration cycle, which can beapplied to an air-conditioning system for automobile use, household useand business use.

[0004] 2. Description of Related Art

[0005]FIG. 22 shows an expansion-valve system refrigeration cycle as oneof typical refrigeration cycles. In the refrigeration cycle, the gaseousrefrigerant of high temperature and high pressure sent out from acompressor CP is introduced into a condenser CD and exchanges heat withthe ambient air to be cooled and condensed therein. The condensedrefrigerant mostly in a liquefied state flows into a receiver-tank RT tobe completely separated into a gaseous refrigerant and a liquefiedrefrigerant. Then, only the liquefied refrigerant flows out of thereceiver-tank RT. The liquefied refrigerant is decompressed and expandedquickly by an expansion-valve EV, and is introduced into an evaporatorEP as a mist-like refrigerant of low pressure and low temperature. Thismist-like refrigerant evaporates in the evaporator EP by absorbinglatent heat from the ambient air to be turned into a gaseousrefrigerant. Then, the gaseous refrigerant flows out of the evaporatorEP, and is inhaled by the compressor CP.

[0006] In FIG. 22, the spotted area indicates that a refrigerant is in aliquid state. In the meantime, the refrigeration flow rate is controlledby adjusting the opening degree of the expansion-valve EV in response tothe signal sent from a heat-sensitive-coupler SC provided at the outletside of the evaporator EP.

[0007] By the way, in a refrigeration cycle for automobile use, it isproposed that a refrigerant condensed in a condenser CD is subcooled toa temperature lower than the condensation temperature of the refrigerantby about several degrees to increase the amount of heat release andthereafter the subcooled refrigerant is introduced into anexpansion-valve EV and an evaporator EP to enhance the refrigeratingcapacity. Concretely, the subcooling portion, which subcools therefrigerant condensed by the condenser CD to a temperature lower thanthe condensation temperature of the refrigerant by several degreescentigrade, is provided so as to send the condensed refrigerant to theevaporator side as a stabilized liquid refrigerant. Usually, thissubcooling portion is arranged at the downstream side of thereceiver-tank RT. In many cases, such a subcooling portion is integrallyprovided to the condenser CD (subcool system condenser) in view of spaceefficiency.

[0008] On the other hand, in many cases, a receiver-dryer is used as theaforementioned receiver-tank RT. The receiver-dryer is provided with adesiccant-filled-portion therein to absorb the moisture components ofthe refrigerant. Such a receiver-dryer includes the so-calledsandwich-type receiver-dryer having an upper space 33 above adesiccant-filled portion 32 and a lower space 34 below thedesiccant-filled portion 32 in a vertical tank 31 as shown in FIGS.23A-23C, and the so-called bag-type receiver-dryer provided with adesiccant-filled portion 32 in one side in a vertical tank 31 as shownin FIG. 23D.

[0009] In the receiver-dryer having a sucking-pipe 36 shown in FIG. 23A,the refrigerant flowed into the upper space 33 via the refrigerant inlet35 passes through the desiccant-filled-portion 32 to reach the lowerspace 34. Then, the liquefied refrigerant separated from the gaseousrefrigerant is sucked up by the sucking-pipe 36 and flows out of therefrigerant outlet 37 provided at the top of the tank.

[0010] In the receiver-dryer having a supplying-pipe 38 shown in FIG.23B, the refrigerant introduced from the refrigerant inlet 35 providedat the bottom portion flows up the supplying-pipe 38 to reach the upperspace 33, and then passes through the desiccant-filled-portion 32 toreach the lower space 34. Then, the liquefied refrigerant separated fromthe gaseous refrigerant flows out of the refrigerant outlet 37 providedat the bottom of the tank.

[0011] In the inlet-outlet-confrontation-type receiver-dryer shown inFIG. 23C, the refrigerant introduced into the upper space 33 via the toprefrigerant inlet 35 passes through the desiccant-filled-portion 32 toreach the lower space 34. Then, the liquefied refrigerant separated fromthe gaseous refrigerant flows out of the refrigerant outlet 37 providedat the bottom of the tank.

[0012] In the bag-type receiver-dryer shown in FIG. 23D, the refrigerantflowed into the tank via the refrigerant inlet 35 provided at the sideportion of the tank contacts the desiccant-filed-portion 32, and theliquefied refrigerant separated from the gaseous refrigerant in thelower portion of the tank flows out of the refrigerant outlet 37provided at the bottom of the tank.

[0013] In an air-conditioning system, it is always desired to improvethe space efficiency and performance. Especially, in an automobileair-conditioner, in order to effectively use the limited body space, itis requested that the whole system be further miniaturized. In order torealize the aforementioned requests, it is necessary to reduce theamount of refrigerant sealed in the refrigeration cycle, to enhance theperformance stability to load fluctuation (overcharge toughness) and toprevent performance deterioration with time due to a continuous running(decline of leakage toughness). For these purposes, it is desired tosecure a steady region, i.e., a stable region in a subcooled state ofthe refrigerant to the amount of sealed refrigerant, as widely aspossible.

[0014]FIG. 8 is a correlation characteristic figure showing thecorrelation between a subcooling degree of the condensed refrigerant andan amount of sealed refrigerant obtained by a charge examination (cyclebench) of an automobile air-conditioner. In this correlationcharacteristic figure, it is ideal that the rising curve is steep untilit reaches a steady region as shown by the phantom-line curve X2 andthat the steady region has a wider range.

[0015] However, in an automobile air-conditioner using a conventionalsubcooling system condenser, the rising curve is gentle until it reachesthe steady region as shown by the solid-line curve Y. Therefore, thesteady region starting point delays toward the larger amount of sealedrefrigerant side, which results in a delayed refrigerant sealing timingand a narrow steady region width. This means that in the conventionalautomobile air-conditioner the miniaturization by decreasing the sealedrefrigerant amount is difficult, the performance stability to loadfluctuation is bad, and the performance tends to deteriorate with timedue to a continuous running.

[0016] The inventors investigated causes of the above-mentioned problemsof the conventional automobile air-conditioner from various aspects soas to realize a miniaturized high-performance automobileair-conditioner. Consequently, the inventors revealed that one factor ofthe above-mentioned problems resides in a structure of a conventionalreceiver-dryer RD. That is, since the interface between the liquefiedrefrigerant and the gaseous refrigerant, i.e., the surface of theliquefied refrigerant, near the refrigerant outlet of the receiver-dryerRD is hard to become stable, the stable supply of the liquefiedrefrigerant to the following cycle part cannot be performed.Furthermore, a large amount of gaseous refrigerant will be mixed intothe liquefied refrigerant to be flowed out. Therefore, theabove-mentioned steady region becomes narrower and the steady regionstarting point delays toward the larger amount of sealed refrigerantside.

[0017] That is, since a refrigerant flow velocity flowing into areceiver-dryer RD from a condenser CD is generally high, in asandwich-type receiver-dryer, larger turbulence of the liquefiedrefrigerant occurs in the upper space 33 into which the refrigerant isintroduced. Consequently, since the liquefied refrigerant stagnates inthe upper space 33, the liquefied refrigerant is not fully supplied tothe lower space 34. As a result, a few amount of liquefied refrigerantaccumulated in the lower space 34 is disturbed by the high-speed liquidflow passed through the desiccant-filled-portion 32, which causesbubbles of gaseous refrigerant. For this reason, it is assumed that agaseous refrigerant flows out of the refrigerant outlet 37 exposed tothe gaseous phase due to large surface fluctuation, and/or a lot of airbubbles are involved into the liquefied refrigerant to be flowed out.

[0018] On the other hand, in the bag-type receiver-dryer, it is assumedthat since the internal refrigerant flow velocity and the turbulence ofthe internal refrigerant are larger than in the sandwich-typereceiver-dryer, the liquefied refrigerant surface near the refrigerantoutlet 37 becomes further unstable, resulting in a larger outflow ofgaseous refrigerant.

[0019] In view of the aforementioned technical background, the presentinvention has been made. It is an object of the present invention toprovide a receiver-tank for a refrigeration cycle which is small insize, light in weight and small in refrigerant amount.

[0020] It is another object of the present invention to provide areceiver-tank for a refrigeration cycle which can enlarge the stableregion of refrigerant to an amount of sealed refrigerant and supply thestable liquefied refrigerant to the following cycle portion.

[0021] It is still another object of the present invention to provide acondensing apparatus for use in a refrigeration cycle in which a surfaceof a liquefied refrigerant separated from a gaseous refrigerant can bestabilized and only the liquefied refrigerant can be supplied from thereceiver-dryer to the subsequent cycle part.

[0022] It is still yet another object of the present invention toprovide a receiver-dryer used for the above-mentioned condensingapparatus in which the surface of the liquefied refrigerant separatedfrom the gaseous refrigerant can be stabilized and only the liquefiedrefrigerant can be supplied to the subsequent cycle part.

[0023] Another object of the present invention will be apparent from thefollowing embodiments.

DISCLOSURE OF THE INVENTION

[0024] According to a first aspect of the present invention, areceiver-tank for use in a refrigeration cycle, wherein a condensedrefrigerant is introduced into the receiver-tank and accumulated thereinand only a liquefied refrigerant flows out of the receiver-tank, thereceiver-tank comprises:

[0025] a tank main body having a refrigerant inlet and a refrigerantoutlet each provided in a bottom wall of the tank main body;

[0026] a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer, theflow-resistance layer being provided in the tank main body such that anupper space is formed above the flow-resistance layer; and

[0027] a suction pipe provided in the tank main body, the suction pipehaving an upper end opened toward the upper space and a lower endcommunicated with the refrigerant outlet,

[0028] whereby a refrigerant introduced into the tank main body via therefrigerant inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the refrigerant outlet viathe suction pipe.

[0029] According to the first aspect of the present invention, thecondensed refrigerant, which is a mixture of a gaseous refrigerant and aliquefied refrigerant, is abruptly diffused into a wide area of theinner bottom portion of the tank main body to thereby reduce the flowvelocity immediately after introduced into the tank main body.Subsequently, the refrigerant goes up through the desiccant-filled-layerto further decrease the flow velocity.

[0030] Therefore, the liquefied refrigerant, which is slow in flowvelocity as compared with a gaseous refrigerant, passes through thedesiccant-filled-layer to reach the upper space, which causes a reducedflow velocity. Accordingly, the liquefied refrigerant accumulates tocreate liquid stagnation in the upper space without causing turbulence.On the other hand, the flow velocity of the gaseous refrigerant alsoabruptly reduces when the gaseous refrigerant passes through thedesiccant-filled-layer.

[0031] For this reason, when the gaseous refrigerant reaches the liquidstagnation created in the upper space, it slowly goes up in the liquidstagnation as bubbles. Consequently, a gaseous refrigerant passesthrough the surface of the liquid stagnation and accumulates above thesurface without disturbing the surface.

[0032] Since the upper end of the suction pipe is located at the bottomof the liquid stagnation stably accumulated in the upper space, only theaccumulated liquefied refrigerant flows into the suction pipe to bedischarged from the refrigerant outlet.

[0033] Since only the liquefied refrigerant stably flows out from thereceiver-dryer as mentioned above, it becomes possible to fill anappropriate amount of refrigerant in the refrigeration cycle at anearlier stage. Moreover, since the steady region between the optimumpoint and the excessive point of refrigerant amount can be expanded byusing the surplus space in the receiver-dryer as a buffer space, thewhole refrigeration cycle can be operated stably.

[0034] In the first aspect of the present invention, it is preferablethat the flow-resistance layer is provided with a plurality ofdispersing passages for dispersing the refrigerant in a radial andoutward direction of the tank main body. For example, theflow-resistance layer may be formed by numerous particles, knittedfabrics, woven fabrics, non-woven fabrics, a porous or perforatedpanel/member or the lamination thereof, or a combination of one or moreof the aforementioned members/materials.

[0035] In the first aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby numerous particle-shaped desiccating agents. That is, in areceiver-tank for use in a refrigeration cycle, desiccating agents aredisposed in the receiver-tank in order to delete the moisture in arefrigerant. Accordingly, in the aforementioned structure, theflow-resistance layer can also be used as desiccating agents.

[0036] Furthermore, in the first aspect of the present invention, it ispreferable that a lower space for diffusing the refrigerant introducedfrom the refrigerant inlet is formed under the flow-resistance-layer inthe tank main body. In cases where the aforementioned structure isemployed, a refrigerant introduced from the refrigerant inlet isdiffused widely in the lower space, to thereby further reduce the flowvelocity. Thus, occurrence of turbulence of refrigerant can be preventedeffectively, resulting in a smooth creation of stable liquid stagnation.

[0037] Furthermore, in the first aspect of the present invention, it ispreferable that a height of the lower space is 25% or less of athickness of the flow-resistance layer. In this case, the lower spacecan be decreased while ensuring the flow decreasing function by thelower space. Therefore, turbulence of refrigerant hardly occurs,enabling an ample supply of liquid refrigerant to the upper space.

[0038] Furthermore, in the first aspect of the present invention, it ispreferable that the suction pipe has an enlarged-diameter portion at anupper end thereof.

[0039] In this case, since the inlet side of the suction pipe forms adented portion at the upper portion of the flow-resistance layer, theliquid refrigerant can be easily flowed into the suction pipe.Furthermore, the flow velocity of the liquefied refrigerant becomesslower than in an on-enlarged-diameter portion. Therefore, even ifbubbles of the gaseous refrigerant exist in the enlarged-diameterportion, the bubbles can go up in the enlarged-diameter portion.

[0040] In order to enhance the function of the enlarged-diameterportion, in the first aspect of the present invention, it is preferableto employ the following structure.

[0041] That is, in the first aspect of the present invention, it ispreferable that the following conditions are satisfied: d1<d2≦3d1, andd1<h1≦5d1, wherein an inner diameter of a non-enlarged-diameter portionof an intermediate portion of the suction pipe, the maximum openingdiameter of the enlarged-diameter portion and a depth of theenlarged-diameter portion are defined by d1, d2 and h1, respectively.

[0042] Furthermore, in the first aspect of the present invention, it ispreferable that an upwardly extended bubble-swallow-prevention wall isformed on a periphery of an upper end opening of the suction pipe. Inthis case, the bubbles of the gaseous refrigerant going up through theliquid stagnation created in the upper space will be hardly swallowed bythe liquefied refrigerant flowing toward the suction pipe because of theexistence of the bubble-swallow-prevention wall. Thus, it is possible toprevent the gaseous refrigerant from being swallowed into the suctionpipe.

[0043] In order to enhance the function of the bubble-swallow-preventionwall, in the first aspect of the present invention, it is preferable toemploy the following structure.

[0044] That is, in the present invention, it is preferable that thefollowing conditions are satisfied: h2≦2d1, wherein an inner diameter ofa non-enlarged-diameter portion of an intermediate portion of thesuction pipe and a height of the bubble-swallow-prevention wall aredefined by d1 and h2, respectively.

[0045] Furthermore, in the present invention, it is preferable that thefollowing conditions are satisfied: 1.5φ≦L1≦0.8 D, wherein a distancebetween a center of the receiver-tank outlet and a center of thereceiver-tank inlet, an inner diameter of the tank main body and anopening diameter of an outlet opening of the receiver-tank inlet aredefined by L1, D and φ, respectively.

[0046] In this case, since the distance between the refrigerant inletand the refrigerant outlet can be kept appropriately, it becomespossible to prevent the upstream of the refrigerant introduced from therefrigerant inlet from being biased toward the refrigerant outlet side,or the suction pipe side, resulting in more stable liquid stagnation.

[0047] Furthermore, it is preferable the following conditions aresatisfied: Ld≦0.7Le, wherein a thickness of the flow-resistance layerand an effective length of the tank main body are defined by Ld and Le,respectively. In this case, enough space for accumulating a gaseousrefrigerant and a liquefied refrigerant above the tank main body can besecured, resulting in a more stable supply of a liquefied refrigerant.

[0048] Furthermore, in the present invention, it is preferable that afilter layer us disposed on at least an upper surface of thedesiccant-filled-layer, or a pair of perforated plates are disposed onupper and lower surfaces of the desiccant-filled-layer. In this case,the refrigerant passing through the filter layer or the perforatedplates is rectified by the filter layer or the perforated plates. Thus,a partial high-speed flow will be extinguished, and a liquefiedrefrigerant and a gaseous refrigerant will be divided into minuterefrigerant. Accordingly, the liquid stagnation in the upper space canbe created stably.

[0049] Furthermore, in the present invention, it is preferable thatinlets are disposed at predetermined circumferential intervals. In thiscase, a refrigerant can be introduced into the tank main body evenlyfrom the periphery of the bottom wall of the tank main body, which canassuredly prevent the generation of bubbles of refrigerant due to theturbulence or the like. As a result, stable liquid stagnation can becreated.

[0050] According to a second aspect of the present invention, areceiver-tank for use in a refrigeration cycle, wherein a condensedrefrigerant is introduced into the receiver-tank and accumulated thereinand only a liquefied refrigerant flows out of the receiver-tank, thereceiver-tank comprises:

[0051] a tank main body having a refrigerant inlet and a refrigerantoutlet each provided in a bottom wall of the tank main body;

[0052] a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer, theflow-resistance layer being provided in the tank main body such that anupper space is formed above the flow-resistance layer;

[0053] a suction pipe provided in the tank main body, the suction pipehaving an upper end opened toward the upper space and a lower endcommunicated with the refrigerant outlet; and

[0054] a desiccating-agent-filled member disposed in the upper space soas to space apart from the flow-resistance layer,

[0055] whereby a refrigerant introduced into the tank main body via therefrigerant inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the refrigerant outlet viathe suction pipe.

[0056] According to the second aspect of the present invention, in thesame manner as in the first aspect of the present invention, since onlythe liquefied refrigerant stably flows out from the receiver-dryer, itbecomes possible to fill an appropriate amount of the refrigerant in therefrigeration cycle at an earlier stage. Moreover, since the steadyregion between the optimum point and the excessive point of refrigerantamount can be expanded by using the surplus space in the receiver-dryeras a buffer space, the whole refrigeration cycle can be operated stably.

[0057] Furthermore, since the desiccating-agent-filled member is formedin the upper space in the tank main body, the moisture of therefrigerant passing through the tank main body can be deleted. Thus, anappropriate refrigerant with no moisture can be discharged, resulting ina stable operation of the entire refrigeration cycle.

[0058] In the second aspect of the present invention, it is preferablethat the flow-resistance layer maybe formed by numerous particles,knitted fabrics, woven fabrics, non-woven fabrics, a porous orperforated panel/member or the lamination thereof, or a combination ofone or more of the aforementioned members/materials, or theflow-resistance layer is provided with a plurality of dispersingpassages for dispersing the refrigerant in a radial and outwarddirection of the tank main body.

[0059] Furthermore, in the second aspect of the present invention, it ispreferable that the flow-resistance layer is a desiccant-filled-layerconstituted by numerous particle-shaped desiccating agents. In thiscase, it becomes possible to supply an enough amount of desiccatingagents as the flow-resistance layer and the desiccating-agent-filledmember.

[0060] In the second aspect of the present invention, it is preferablethat desiccating-agent-filled member is immovably disposed or movablydisposed in the upper space.

[0061] Furthermore, in the second aspect of the present invention, it ispreferable that the following conditions are satisfied: Ld<D, wherein athickness of the desiccating-agent-filled member and an inner diameterof the tank main body are defined by Ld and D, respectively. In thiscase, an enough space for accumulating the liquefied refrigerant and thegaseous refrigerant above the tank main body can be secured, resultingin a steady supply of liquefied refrigerant.

[0062] Furthermore, in the second aspect of the present invention, it ispreferable that a lower space for diffusing the refrigerant introducedfrom the refrigerant inlet is formed under the flow-resistance-layer inthe tank main body. In this case, the refrigerant introduced from therefrigerant inlet diffuses widely in the lower space, resulting in areduced flow velocity. Thus, generation of turbulence in the lower spacecan be prevented more assuredly, which enables to create stable liquidstagnation.

[0063] Furthermore, in the second aspect of the present invention, it ispreferable that the refrigerant outlet is formed at a center of thebottom wall of the tank main body and a plurality of the refrigerantinlets are formed around the refrigerant outlet. In this case, itbecomes possible to introduce a refrigerant into the tank main body fromthe peripheral portion of the bottom of the tank main body in adispersed manner. Thus, generation of bubbles due to a biased flowand/or turbulence of refrigerant can be effectively prevented, whichenables to create further stable liquid stagnation.

[0064] Furthermore, in the second aspect of the present invention, it ispreferable that the plurality of the refrigerant inlets are disposed atpredetermined circumferential intervals. In this case, the refrigerantcan be introduced evenly into the tank main body from the peripheralportion of the bottom wall of the tank main body. Thus, generation ofbubbles due to a biased flow and/or turbulence of refrigerant can beeffectively prevented, which enables to create further stable liquidstagnation.

[0065] On the other hand, the aforementioned receiver-tank according tothe first aspect of the present invention can be integrally assembled toa heat exchanger such as a condenser to form a heat exchanger with areceiver-tank.

[0066] According to a third aspect of the present invention, a heatexchanger with a receiver-tank, comprises:

[0067] a heat exchanger body including a pair of headers disposed inparallel at a certain distance, a plurality of heat exchanging tubeswith both ends thereof connected to the pair of headers and a condensingportion outlet for discharging a refrigerant condensed while passingthrough the heat exchanging tubes;

[0068] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of the receiver-tank, thereceiver-tank accumulating a refrigerant introduced from thereceiver-tank inlet and discharging only a liquefied refrigerant fromthe receiver-tank outlet; and

[0069] a refrigerant passage for introducing the refrigerant flowed outof the condensing portion outlet into the receiver-tank inlet,

[0070] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer is provided in thereceiver-tank such that an upper space is formed above theflow-resistance layer,

[0071] wherein a suction pipe is provided in the tank main body, thesuction pipe having an upper end opened toward the upper space and alower end communicated with the refrigerant outlet,

[0072] whereby a refrigerant introduced into the tank main body via therefrigerant inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the refrigerant outlet viathe suction pipe.

[0073] In the third aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby numerous particle-shaped desiccating agents, or a lower space fordiffusing the refrigerant introduced from the refrigerant inlet isformed under the flow-resistance-layer in the tank main body.

[0074] Furthermore, the receiver-tank according to the first aspect ofthe present invention can be integrally assembled to a heat exchangerhaving a condensing portion and a subcooling portion to form a heartexchanger with a receiver-tank such as a subcooling system condenser.

[0075] According to the fourth aspect of the present invention, a heatexchanger with a receiver-tank, comprises:

[0076] a heat exchanger body including a pair of headers disposed inparallel at a certain distance, a plurality of heat exchanging tubeswith both ends thereof connected to the pair of headers, partitioningmembers each partitioning an inside of the header to thereby group theplurality of heat exchanging tubes into a condensing portion and asubcooling portion, a condensing portion outlet for discharging arefrigerant condensed while passing through the heat exchanging tubesand a subcooling portion inlet for introducing a refrigerant into thesubcooling portion;

[0077] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of the receiver-tank, thereceiver-tank accumulating a refrigerant introduced from thereceiver-tank inlet and discharging only a liquefied refrigerant fromthe receiver-tank outlet; and

[0078] a refrigerant passage for introducing the refrigerant dischargedfrom the condensing portion outlet into the receiver-tank inlet andintroducing the refrigerant discharged from the receiver-tank outletinto the subcooling portion inlet,

[0079] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer is provided in thereceiver-tank such that an upper space is formed above theflow-resistance layer, and

[0080] wherein a suction pipe provided in the tank main body, thesuction pipe having an upper end opened toward the upper space and alower end communicated with the refrigerant outlet,

[0081] whereby a refrigerant introduced into the tank main body via thereceiver-tank inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the receiver-tank outlet viathe suction pipe.

[0082] In the fourth aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby numerous particle-shaped desiccating agents.

[0083] According to the fifth aspect of the present invention, a heatexchanger with a receiver-tank, comprising:

[0084] a heat exchanger body including a pair of headers disposed inparallel at a certain distance, a plurality of heat exchanging tubeswith both ends thereof connected to the pair of headers and a condensingportion outlet for discharging a refrigerant condensed while passingthrough the heat exchanging tubes;

[0085] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of the receiver-tank, thereceiver-tank accumulating a refrigerant introduced from thereceiver-tank inlet and discharging only a liquefied refrigerant fromthe receiver-tank outlet; and

[0086] a refrigerant passage for introducing the refrigerant flowed outof the condensing portion outlet into the receiver-tank inlet,

[0087] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer is provided in thereceiver-tank such that an upper space is formed above theflow-resistance layer,

[0088] wherein a suction pipe is provided in the tank main body, thesuction pipe having an upper end opened toward the upper space and alower end communicated with the receiver-tank outlet, and

[0089] wherein a desiccating-agent-filled member is disposed in theupper space so as to space apart from the flow-resistance layer,

[0090] whereby a refrigerant introduced into the tank main body via thereceiver-tank inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the receiver-tank outlet viathe suction pipe.

[0091] In the fifth aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby numerous particle-shaped desiccating agents.

[0092] Furthermore, in the fifth aspect of the present invention, it ispreferable that desiccating-agent-filled member is immovably or movablydisposed in the upper space.

[0093] The receiver-tank according to the second aspect of the presentinvention can be integrally assembled to a heat exchanger having acondensing portion and a subcooling portion to form a heat exchangerwith a receiver-tank such as a subcooling system condenser.

[0094] According to the sixth aspect of the present invention, a heatexchanger with a receiver-tank, comprising:

[0095] a heat exchanger body including a pair of headers disposed inparallel at a certain distance, a plurality of heat exchanging tubeswith both ends thereof connected to the pair of headers, partitioningmembers each partitioning an inside of the header to thereby group theplurality of heat exchanging tubes into a condensing portion and asubcooling portion, a condensing portion outlet for discharging arefrigerant condensed while passing through the heat exchanging tubesand a subcooling portion inlet for introducing the refrigerant into thesubcooling portion;

[0096] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of the receiver-tank, thereceiver-tank accumulating a refrigerant introduced from thereceiver-tank inlet and discharging only a liquefied refrigerant fromthe receiver-tank outlet; and

[0097] a refrigerant passage for introducing the refrigerant dischargedfrom the condensing portion outlet into the receiver-tank inlet andintroducing the refrigerant discharged from the receiver-tank outletinto the subcooling portion inlet,

[0098] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer is provided in thereceiver-tank such that an upper space is formed above theflow-resistance layer,

[0099] wherein a suction pipe is provided in the tank main body, thesuction pipe having an upper end opened toward the upper space and alower end communicated with the receiver-tank outlet, and

[0100] wherein a desiccating-agent-filled member is disposed in theupper space so as to space apart from the flow-resistance layer,

[0101] whereby a refrigerant introduced into the tank main body via thereceiver-tank inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the receiver-tank outlet viathe suction pipe.

[0102] In the sixth aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby numerous particle-shaped desiccating agents.

[0103] The receiver-tank according to the first aspect of the presentinvention can constitute a condensing apparatus for use in arefrigeration cycle together with a condenser such as a header-typecondenser and a serpentine-type condenser.

[0104] According to a seventh aspect of the present invention, acondensing apparatus for use in a refrigeration cycle, the condensingapparatus comprises:

[0105] a condenser including a condensing portion for condensing arefrigerant and a condensing portion outlet for discharging therefrigerant condensed by the condensing portion;

[0106] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of the receiver-tank, thereceiver-tank accumulating a refrigerant introduced from thereceiver-tank inlet and discharging only a liquefied refrigerant fromthe receiver-tank outlet; and

[0107] a refrigerant passage for introducing the refrigerant flowed outof the condensing portion outlet into the receiver-tank inlet,

[0108] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through the flow-resistance layer is provided in thereceiver-tank such that an upper space is formed above theflow-resistance layer, and

[0109] wherein a suction pipe is provided in the tank main body, thesuction pipe having an upper end opened toward the upper space and alower end communicated with the receiver-tank outlet,

[0110] whereby a refrigerant introduced into the tank main body via thereceiver-tank inlet passes through the flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in the upper space,and the liquefied refrigerant flows out of the receiver-tank outlet viathe suction pipe.

[0111] Furthermore, the receiver-tank according to the second aspect ofthe present invention can constitute a condensing apparatus for use in arefrigeration cycle together with a condenser such as a header-typecondenser and a serpentine-type condenser.

[0112] According to the eighth aspect of the present invention, acondensing apparatus for use in a refrigeration cycle, said condensingapparatus comprising:

[0113] a condenser including a condensing portion for condensing arefrigerant and a condensing portion outlet for discharging therefrigerant condensed by said condensing portion;

[0114] a receiver-tank having a receiver-tank inlet and a receiver-tankoutlet each formed in a bottom wall of said receiver-tank, saidreceiver-tank accumulating a refrigerant introduced from saidreceiver-tank inlet and discharging only a liquefied refrigerant fromsaid receiver-tank outlet; and

[0115] a refrigerant passage for introducing the refrigerant flowed outof said condensing portion outlet into said receiver-tank inlet,

[0116] wherein a flow-resistance layer for reducing a flow velocity of arefrigerant passing through said flow-resistance layer is provided insaid receiver-tank such that an upper space is formed above saidflow-resistance layer,

[0117] wherein a suction pipe is provided in said tank main body, saidsuction pipe having an upper end opened toward said upper space and alower end communicated with said receiver-tank outlet, and

[0118] wherein a desiccating-agent-filled member is disposed in saidupper space so as to space apart from said flow-resistance layer,

[0119] whereby a refrigerant introduced into said tank main body viasaid receiver-tank inlet passes through said flow-resistance layerupward to cause liquid stagnation of a liquefied refrigerant in saidupper space, and the liquefied refrigerant flows out of saidreceiver-tank outlet via said suction pipe.

[0120] In the eighth aspect of the present invention, it is preferablethat the flow-resistance layer is a desiccant-filled-layer constitutedby particle-shaped desiccating agents.

[0121] Other objects and the features will be apparent from thefollowing detailed description of the present invention with referenceto the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0122] The present invention will be more fully described and betterunderstood from the following description, taken with the appendeddrawings, in which:

[0123]FIG. 1 is a schematic front view showing a heat exchanger with areceiver-tank according to a first embodiment of the present invention;

[0124]FIG. 2 is a schematic vertical front cross-sectional view showingthe receiver-tank of the first embodiment;

[0125]FIG. 3 is a front view showing a heat exchanger with areceiver-tank according to a second embodiment of the present invention;

[0126]FIG. 4 is a schematic front cross-sectional view showing arefrigerant flow in the heat exchanger of the second embodiment;

[0127]FIG. 5 is an enlarged cross-sectional view showing thereceiver-tank of the second embodiment;

[0128]FIG. 6 is a schematic cross-sectional view showing thereceiver-tank of the second embodiment;

[0129]FIG. 7A is a cross-sectional view showing the central portion ofthe receiver-tank according to a first modification of the secondembodiment;

[0130]FIG. 7B is a cross-sectional view showing the central portion ofthe receiver-tank according to a second modification of the secondembodiment;

[0131]FIG. 8 is a graph showing the correlation between a subcoolingdegree of a condensed refrigerant and an amount of sealed refrigerant;

[0132]FIG. 9 is a front view showing the side portion of the heatexchanger with a receiver-tank according to a third embodiment of thepresent invention;

[0133]FIG. 10 is an enlarged front cross-sectional view showing the heatexchanger with a receiver-tank of the third embodiment;

[0134]FIG. 11 is an enlarged front cross-sectional view showing theblock flange and therearound of the heat exchanger according to thethird embodiment in a disconnected state;

[0135]FIG. 12 is a bottom view showing the inlet-and-outlet formingmember of the receiver-tank of the heat exchanger according to the thirdembodiment;

[0136]FIG. 13 is a schematic cross-sectional view showing thereceiver-tank of the third embodiment;

[0137]FIG. 14 is an enlarged schematic cross-sectional view showing thelower portion of the receiver-tank of the third embodiment;

[0138]FIG. 15 is a horizontal cross-sectional view showing the bracketand therearound of the heat exchanger of the third embodiment;

[0139]FIG. 16 is a top view showing the bracket main body employed inthe third embodiment;

[0140]FIG. 17 is a top view showing the covering member of the bracketapplied in the third embodiment;

[0141]FIG. 18 is a schematic front cross-sectional view showing areceiver-tank for use in a refrigeration system according to a fourthembodiment;

[0142]FIG. 19 is a schematic front cross-sectional view showing a lowerportion of a receiver-tank for use in a refrigeration system accordingto a fifth embodiment;

[0143]FIG. 20A is a cross-sectional view showing the upper portion ofthe desiccant-filled-layer of the receiver-tank according to a firstmodification of the fifth embodiment;

[0144]FIG. 20B is a cross-sectional view showing the upper portion ofthe desiccant-filled-layer of the receiver-tank according to a secondmodification of the fifth embodiment;

[0145]FIG. 21 is a graph showing the relationship between a subcoolingdegree of a condensed refrigerant and an amount of sealed refrigerantobtained by a charge test in a refrigeration cycle;

[0146]FIG. 22 is a refrigerant circuit diagram of a refrigeration cycle;

[0147]FIG. 23A is a schematic vertical cross-sectional view of a firstconventional receiver-tank;

[0148]FIG. 23B is a schematic vertical cross-sectional view of a secondconventional receiver-tank;

[0149]FIG. 23C is a schematic vertical cross-sectional view of a thirdconventional receiver-tank; and

[0150]FIG. 23D is a schematic vertical cross-sectional view of a fourthconventional receiver-tank.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0151] Preferred embodiments of the present invention will now bedescribed, in detail, with reference to the accompanying drawings.

[0152] [First Embodiment]

[0153]FIG. 1 is a schematic front view showing a heat exchanger(condenser) with a receiver-tank according to a first embodiment of thepresent invention. As shown in FIG. 1, this heat exchanger is comprisedof the so-called multi-flow type heat exchanger body 100 and areceiver-tank 130.

[0154] The heat exchanger body 100 is provided with a pair of right andleft vertical headers 101 and 101 spaced apart from each other. Betweenthe pair of headers 101 and 101, a plurality of flat heat exchangingtubes are disposed horizontally at certain intervals with both endsthereof communicated with the corresponding headers 101 and 101. In thepredetermined portions of each header 101 and 101, partition members 102are provided to thereby divide the heat exchanging tubes into aplurality of groups forming paths P1 to P5. Among these paths, the firstpath P1 to the third path P3 constitute a condensing portion 110, andthe fourth and fifth paths P4 and P5 constitute a subcooling portion 120which is independent from the condensing portion 110.

[0155] At the upper portion of the right-hand header 101 and the lowerportion of the left-hand header 101 corresponding to the condensingportion 110, a condensing portion inlet 111 and a condensing portionoutlet 112 are provided, respectively. Furthermore, at the upper andlower end portions of the left-hand header 101 corresponding to thesubcooling portion 120, a subcooling portion inlet 121 and a subcoolingportion outlet 122 are provided, respectively.

[0156] As shown in FIG. 2, a receiver-tank 130 is comprised of avertically disposed cylindrical-type tank main body 140 and aninlet-and-outlet forming member 150 constituting a bottom wall of thetank main body 140. The inlet-and-outlet member 150 is provided with areceiver-tank inlet 131 and a receiver-tank outlet 132.

[0157] In the lower-half portion of the tank main body 140, desiccantseach having a spherical particle shape, such as molecular sieves, arefilled to form a desiccant-filled-layer 135 such that an upper space 160is formed above the desiccant-filled-layer 135 in the tank main body140.

[0158] Furthermore, in the tank main body 140, a refrigerant suctionpipe 133 is arranged along the axis of the tank main body 140 such thatthe lower end thereof is connected to the receiver-tank outlet 132 andthe upper end thereof is opened to the bottom portion of the upper space160, i.e., a portion near the upper surface of thedesiccant-filled-layer 135 in the upper space 160.

[0159] The receiver-tank inlet 131 and the receiver-tank outlet 132 ofthis receiver-tank 130 are to be connected with the condensing portionoutlet 112 and the subcooling portion inlet 121 of the heat exchangerbody 100, respectively. This heat exchanger with the receiver-tank isused as a condenser for an automobile air-conditioning refrigerationsystem together with a compressor, a decompressing means such as anexpansion valve and an evaporator in the same manner as in theaforementioned conventional system. In this refrigeration cycle, thegaseous refrigerant of high temperature and high pressure compressed bythe compressor flows into the condensing portion 110 via thecondensing-portion inlet 111 of the heat exchanger body 100.

[0160] The gaseous refrigerant flowed into the condensing portion 110via the condensing-portion inlet port 111 exchanges heat with theambient air while passing through each path P1 to P3 of the condensingportion 110 in this order to be condensed. The condensed refrigerant asa mixture of a gaseous refrigerant and a liquefied refrigerant is ledinto the receiver-tank 130 via the condensing portion outlet 112.

[0161] The refrigerant as a mixture of a gaseous refrigerant and aliquefied refrigerant flowed into the receiver-tank 130 is rapidlyspread in the bottom portion of the tank main body 140, reducing theflow velocity, and goes upward through the desiccant-filled-layer135.Thus, the desiccant-filled-layer135 functions as a flow-resistance layerfor reducing the upward flow velocity of the refrigerant. Accordingly, aliquefied refrigerant whose flow velocity is slower than that of agaseous refrigerant passes through the desiccant-filled-layer 135 at alow speed. When the liquefied refrigerant reaches the upper space 160,the flow velocity is fully reduced. Therefore, liquid-stagnation R willbe created without causing any disturbance in the upper space 160.

[0162] On the other hand, when the gaseous refrigerant goes up throughthe desiccant-filled-layer 135, the flow velocity is reduced rapidly.Therefore, when the gaseous refrigerant reaches the aforementionedliquid-stagnation R formed in the upper space 160, the gaseousrefrigerant goes up quietly as bubbles in the accumulated liquefiedrefrigerant, and extinguishes at the surface of the accumulatedliquefied refrigerant without causing any disturbance of the liquidsurface. Thus, the gaseous refrigerant will be stored above the liquidsurface in the upper space.

[0163] As mentioned above, the stable liquid-stagnation R is formedabove the desiccant-filled-layer 135 as mentioned above, and that theinlet side end of the refrigerant suction pipe 133 is opened toward thebottom of the liquid-stagnation R. Accordingly, only the liquefiedrefrigerant forming the stabilized liquid-stagnation R flows out of thereceiver-tank outlet 132, and then flows into the subcooling zone 120 ofthe heat exchanger body 100.

[0164] The liquefied refrigerant flowed into the subcooling portion 120passes through the fourth and fifth passes P4 and P5 while exchangingheat with the ambient air to be subcooled. Thereafter, the subcooledrefrigerant flows out of the subcooling portion outlet 122, and then isintroduced into a decompressing means and an evaporator in this order.Thus, the refrigerant circulates in the refrigeration cycle.

[0165] As mentioned above, in the heat exchanger with the receiver-tankaccording to this embodiment, since the condensed refrigerant introducedin the receiver-tank 130 forms the liquid-stagnation R quietly andslowly and the bubbles of the gaseous refrigerant extinguishes smoothlyand efficiently, the stable range of the amount of sealed refrigerantcan be expanded. This enables only the stable liquefied refrigerant tobe extracted assuredly. Accordingly, since the stable supply of theliquefied refrigerant into the subcooling portion 120 can be performed,the supercooling function of the subcooling portion 120 can be attainedto the maximum extent, resulting in sufficient subcooling. As a result,the refrigeration cycle can be operated stably, resulting in enhancedrefrigeration performance.

[0166] Furthermore, since liquefied refrigerant can be supplied stably,the receiver-tank 130 can be decreased in diameter and enhanced inperformance. As a result, the entire refrigerant system can be decreasedin size and weight, which in turn can reduce the amount of refrigerant.

[0167] In the aforementioned embodiment, although the flow-resistancelayer is constituted by the desiccant-filled-layer 135, the presentinvention is not limited to it. For example, the flow-resistance layermay be formed by numerous particles, knitted fabrics, woven fabrics,non-woven fabrics, a porous or perforated panel/member or the laminationthereof, or a combination of one or more of the aforementionedmembers/materials. In the following embodiments and its modifications,the aforementioned various member/materials may also be used as aflow-resistance layer.

[0168] [Second Embodiment]

[0169] FIGS. 3 to 6 show a heat exchanger with a receiver-tank accordingto a second embodiment of the present invention.

[0170] As shown in these Figures, this heat exchanger with areceiver-tank is equipped with a heat exchanger body 210 and areceiver-tank RD.

[0171] The heat exchanger body 210 is a subcool system condenser inwhich a condensing portion C and a subcooling portion S are integrallyprovided. This heat exchanger 210 is provided with a pair of right andleft vertical headers 211 b and 211 a spaced apart from each other and aplurality of flat heat exchanging tubes 212 disposed horizontallybetween the headers 211 a and 211 b at certain intervals with both endsof thereof being communicated with the corresponding headers 211 a and211 b. A corrugated fin 213 is arranged on the outside of each outermostheat exchanging tube 212. Between the adjacent heat exchanging tubes 212and 212, corrugated fins 213 are arranged. A side plate 214 forprotecting the corrugated fin 213 is arranged on the outside of eachoutermost heat exchanging tube 212.

[0172] In the lower portion of each header 211 a and 211 b, partitionmembers 216 each for dividing the inside of the header are provided atthe same height. The upper side of the condenser 210 above the partitionmembers 216 and 216 and the lower side thereof below the partitionmembers 216 and 216 constitute a condensing portion C and a subcoolingportion S, respectively. In the condensing portion C, the aforementionedplurality of tubular elements 212 are divided into the first path C1 tothe third path C3 by partition members 215 and 215 provided in theheaders 211 a and 211 b at predetermined positions.

[0173] Furthermore, at the upper and lower end portions of theright-hand header 211 b, a condensing portion inlet 217 a and asubcooling portion outlet 218 b are provided, respectively. At the lowerend portion of the left-hand header 211 a corresponding to thecondensing portion C and the lower end portion corresponding to thesubcooling portion S, a condensing portion outlet 217 b and a subcoolingportion inlet 218 a are provided, respectively.

[0174] The receiver-tank RD has a vertically disposed cylindrical tankmain body 201 in which a desiccant-filled-layer 202 as a flow-resistancelayer is provided. In the tank main body 201, an upper space 203 isformed above the desiccant-filled-layer 202 and a lower space 204 isformed below the desiccant-filled-layer 202. At the position apart fromthe center of an inlet-and-outlet forming member 201 a as a bottom wallof the tank main body 201, a receiver-tank inlet 205 having an outletopening 205 a opened toward the lower space 204 is formed.

[0175] Furthermore, a receiver-tank outlet 206 b is penetrated in thecenter of the inlet-and-outlet forming member 201 a along the axialdirection thereof. A suction pipe 260 is disposed in the tank main body201 along the central axis thereof with the lower end connected to thereceiver-tank outlet 206 b. Thus, in this embodiment, the receiver-tankoutlet 206 b and the suction pipe 260 constitute therefrigerant-discharging-passage 206. The refrigerant-discharging-passage206 has an inlet 206 a which opens toward the upper space 203 at theupper end central portion of the desiccant-filled-layer 202. Therefrigerant-discharging-passage 206 extends along the central axis ofthe tank main body 201 and penetrates the central portion of theinlet-and-outlet forming member 201 a to be communicated with theexterior of the tank main body 201.

[0176] The inlet 206 a has an enlarged-diameter-portion 261 in the shapeof a bell which opens toward the upper space 203. Moreover, thedesiccant-filled-layer 202 includes upper and lower porous plates 221 aand 221 b and spherical desiccant particles 202 a filled between theseplates 221 a and 221 b. Between the upper porous plate 221 a and the topof the filled spherical desiccant particles 202 a, a filter 207 made offine porous materials is disposed.

[0177] The inlet 205 b of the receiver-tank inlet 205 of thereceiver-dryer RD is connected to the condensing portion outlet 217 b ofthe subcooling system condenser 210. Moreover, the receiver-tank outlet206 b is communicated with the subcooling portion inlet 218 a via anL-shaped pipe 219.

[0178] In the above-mentioned heat exchanger with a receiver-tank, asshown in FIG. 4, the gaseous refrigerant of high temperature and highpressure from the compressor CP of the refrigeration cycle is introducedinto the condensing portion C via the condensing portion inlet 217 a ofthe heat exchanger main body 210. The gaseous refrigerant passes throughthe first path C1 to the third path C3 in turn. When passing throughthese paths C1 to C3, the gaseous refrigerant exchanges heat with theambient air to be condensed, and flows into the receiver dryer RD viathe condensing portion outlet 217 b as a mixture of a gaseousrefrigerant and a liquefied refrigerant.

[0179] The refrigerant, which is a mixture of a gaseous refrigerant anda liquefied refrigerant, is separated into the gaseous refrigerant andthe liquefied refrigerant in the receiver-dryer RD. Then, the liquefiedrefrigerant passes through the refrigerant-discharging-passage 206 andflows into the subcooling portion S via the subcooling portion inlet 218a. In the subcooling portion S, the liquefied refrigerant furtherexchanges heat with the ambient air to be subcooled. The subcooledrefrigerant is then sent to the following cycle part (evaporator side)via the subcooling portion outlet 218 b.

[0180] In the meantime, the refrigerant, which is a mixture of a gaseousrefrigerant and a liquefied refrigerant sent from the condensing portionC of the heat exchanger body 210, is sent into the receiver-dryer RD ata high flow velocity. However, when the refrigerant flows into the lowerspace 204 through the receiver-tank inlet 205, it diffuses widely,resulting in a decreased flow velocity.

[0181] Furthermore, since the desiccant-filled-layer 202 functions as aresistance layer to the refrigeration flow going up through thedesiccant-filled-layer 202, the upstream flow velocity is reducedremarkably and the refrigerant slowly flows into the upper space 203.Especially, in this embodiment, the refrigerant passing through betweenthe spherical particles 202 a of the desiccant-filled-layer 202 changesits direction frequently to take a long course. Therefore, the flowvelocity reduces remarkably and a local high velocity flow alsodisappears due to the rectification function, resulting in an uniformupstream flow. Moreover, when passing through the filter 207, theliquefied refrigerant and the gaseous refrigerant will be dispersedfinely.

[0182] Therefore, the liquefied refrigerant, which is slow in flowvelocity as compared with a gaseous refrigerant, passes through thedesiccant-filled-layer 202 to reach the upper space 203, which resultsin a further reduced flow velocity. Accordingly, the liquefiedrefrigerant accumulates in the upper space 203 to form liquid-stagnationR without causing turbulence. On the other hand, the flow velocity ofthe gaseous refrigerant is also abruptly reduced when the gaseousrefrigerant passes through the desiccant-filled-layer 202.

[0183] Accordingly, when the gaseous refrigerant reaches theliquid-stagnation R accumulated in the upper space 203, it calmly goesup in the liquid-stagnation R as bubbles B. Consequently, the gaseousrefrigerant goes up to the surface of the liquid-stagnation R andaccumulates above the surface thereof without disturbing the surface. Asa result, the surface F of the liquid-stagnation R stabilizes withlittle fluctuation.

[0184] On the other hand, since the inlet 206 a of therefrigerant-discharging-passage 206 is located at the bottom of theliquid-stagnation R stably accumulated in the upper space 203, only theliquefied refrigerant of the liquid-stagnation R flows into therefrigerant-discharging-passage 206 via the inlet 206 a thereof, and isthus stably supplied to the subcooling portion S.

[0185] In this case, since the enlarged-diameter-portion 261 formed atthe inlet 206 a of the refrigerant-discharging-passage 206 serves as adented portion at the upper end of the desiccant-filled-layer 202, theliquefied refrigerant easily flows into therefrigerant-discharging-passage 206.

[0186] Furthermore, since the flow velocity at theenlarged-diameter-portion 261 is slower than that at the inner side ofthe non-enlarged-diameter portion of the refrigerant-discharging-passage206, even if bubbles B of the gaseous refrigerant appears near the inlet206 a, the bubbles B easily goes upward in the enlarged-diameter-portion261. Therefore, very few bubbles B are involved in the liquefiedrefrigerant flowing into the refrigerant-discharging-passage 206.

[0187] Therefore, in the subcooling portion S, the subcooling functioncan be demonstrated to the maximum extent, which can secure a sufficientsubcooling area. In the refrigeration cycle including such a condensingapparatus employing the aforementioned receiver-dryer RD, it is possibleto fill an appropriate amount of the refrigerant at an earlier stage.

[0188] Moreover, since the steady region between the optimum point andthe excessive point of refrigerant amount can be expanded by using thesurplus space in the tank main body 201 as a buffer space, the stableoperation of the whole refrigeration cycle can be performed.Furthermore, since the operation pressure can be kept low, a requiredpower can be reduced, resulting in an improved system coefficient.

[0189] The above-mentioned action can be explained by using thecorrelation characteristic between the subcooling degree of thecondensed refrigerant and the amount of sealed refrigerant obtained bythe charge examination shown in FIG. 8 as follows. The subcooling degreegoes up sharply and reaches the steady region start point at the fewersealed refrigerant side, and the width of steady region becomes wider.In other words, it means that the curve Y approaches the ideal curve X2shown by the phantom line in FIG. 8.

[0190] Therefore, in the automobile air conditioner using this heatexchanger, the miniaturization of the heat exchanger by decreasing thesealed refrigerant amount can be easily performed, the performancestability to load fluctuation can be improved and the performancedeterioration with time due to a continuous running can also beprevented effectively.

[0191] Moreover, since the structure of therefrigerant-discharging-passage 206 and the receiver-tank inlet 205 ofthe receiver-dryer RD differ slightly as compared to those of a heatexchanger in a conventional refrigeration cycle, an existing condenserincluding a subcooling portion can be used as it is. As for thereceiver-dryer RD, it is not required to drastically change thefundamental structure of a conventional receiver-dryer. Furthermore,since the desiccant-filled-layer 202 itself demonstrates a rectificationfunction, special rectification means such as a rectification board canbe omitted, which is advantageous in manufacturing cost.

[0192] In addition, the refrigerant-discharging-passage 206 of thereceiver-dryer RD in the aforementioned embodiment has anenlarged-diameter-portion 261 which upwardly opens in the shape of abell. However, as shown in FIG. 7A, the enlarged-diameter-portion 262may be discontinuously enlarged to the inner side(non-enlarged-diameter-portion) of the refrigerant-discharging-passage206.

[0193] In order to effectively obtain the functions caused by theenlarged-diameter-portion 261 or 262 of therefrigerant-introducing-passage 206, it is recommended to satisfy thefollowing conditions: d1<d2≦3d1, and d1<h1≦5d1, wherein the innerdiameter of the non-enlarged-diameter-portion of the inlet of therefrigerant-discharging-passage 206, the maximum opening diameter of theenlarged-diameter-portion 261 or 262 and the depth of theenlarged-diameter-portion 261 or 262 are defined by d1, d2 and h1,respectively.

[0194] Moreover, it is preferable that the depth hi of theenlarged-diameter-portion 261 or 262 is not larger than the longitudinallength Ld of the desiccant-filled-layer 202, i.e., it is preferable tosatisfy the following condition: h1≦Ld.

[0195]FIG. 7B shows a further modification of a receiver-dryer RD.

[0196] In this receiver-dryer RD, a bubble-swallow-prevention wall 208of a cylindrical shape is formed at the opening peripheral edge of theenlarged inlet 206 a of the refrigerant-discharging-passage 206.Therefore, the bubbles B of the gaseous refrigerant going up through theliquid-stagnation R in the upper space 203 is hardly involved into theliquid-stagnation R flowing toward the inlet 206 a, resulting in adecrease amount of gaseous refrigerant flowed into therefrigerant-discharging-passage 206.

[0197] In order to effectively obtain the function of thebubble-swallow-prevention wall 208 without causing any interruption ofthe liquefied refrigerant flow into the refrigerant-discharging-passage206, it is preferable that the following condition is satisfied: h2≦2d1,wherein the inner diameter of the refrigerant-discharging-passage 206and the height of the bubble-swallow-prevention wall 208 are defined bydl and h2, respectively.

[0198] Furthermore, in the receiver-dryer RD according to the presentinvention, the size and arrangement of each part can be set arbitrarily.However, it is preferable that the following conditions are satisfied:1.5φ≦L1≦0.8D, wherein the distance between the center of therefrigerant-introducing-passage 205 and the center of therefrigerant-discharging-passage 206, the inner diameter of the tank mainbody 201 and the opening diameter of the outlet opening of thereceiver-tank inlet 205 are defined by L1, D and φ, respectively (seeFIG. 6).

[0199] In this case, since the opening center of the receiver-tank inlet205 and the outlet center of the refrigerant-discharging-passage 206 aremoderately apart from each other, the upstream flow of the refrigerantintroduced from the receiver-tank inlet 5 will not be concentrated onthe inlet 206 a side of the refrigerant-discharging-passage 206, whichfurther reduces the refrigerant flow velocity and further stabilizes therefrigerant surface.

[0200] On the other hand, it is not recommended that the above-mentioneddistance L1 is too short, and/or the receiver-tank inlet 205 has acylindrical shape surrounding the refrigerant-discharging-passage 206because the upstream flow through the receiver-tank inlet 205 willconcentrate on the inlet 206 a side of therefrigerant-discharging-passage 206 and thereby a decrease of therefrigerant flow velocity near the refrigerant-discharging-passage 206may become inadequate and a stable liquid surface of theliquid-stagnation R in the upper space 203 cannot be obtained.

[0201] In the above-mentioned embodiment, the lower space 204 is formedunderneath the desiccant-filled-layer 202 in the tank main body 201.Instead, the desiccant-filled-layer 202 may be disposed on the innerbottom of the tank main body 201 without forming the aforementionedlower space 204 so that the refrigerant from the receiver-tank inlet 205flows directly into the desiccant-filled-portion 202.

[0202] However, if the lower space 204 exists, there is an advantagesuch that the diffusion of refrigerant flowed from the receiver-tankinlet 205 can be made smoothly and therefrigerant-flow-velocity-decrease-functions due to the aforementioneddiffusion becomes effective. If the height of the lower space 204 is setto 25% or less of the vertical length of the desiccant-filled-layer 202,a turbulent flow region will not be produced. Furthermore, since thereis no room to generate a large amount of liquid-stagnation, a supply ofthe liquefied refrigerant to the upper space 203 can be fully secured.Moreover, the lower space 204 may be filled up with a resistance objectwhich permits a flow of a liquefied refrigerant and a gaseousrefrigerant.

[0203] In order to obtain a sufficient space for accumulating aliquefied refrigerant and a gaseous refrigerant in the upper space 203of the tank main portion 201, it is desirable that the followingcondition is satisfied: Ld≦0.7Le, wherein the vertical length of thedesiccant-filled-portion 202 and an effective vertical length of thetank main body 201 are defined by Ld and Le, respectively.

[0204] In addition, in a case where a receiver-dryer RD is used in aninclined state, the inlet 206 a of the refrigerant-discharging-passage206 is set to be located below the center of the inclined tank main body201.

[0205] Although the heat exchanger according to the present inventioncan be suitably applied especially for a refrigeration cycle having asubcooling portion in addition to a condensing portion as in theaforementioned embodiment, it is also applicable to variousrefrigeration cycles with no subcooling portion. Moreover, thesubcooling portion maybe included in a refrigeration cycle as anindependent heat exchanger instead of being integrally provided to thecondenser like the subcooling system condenser of the aforementionedembodiment. Furthermore, the condenser may be the so-called parallelflow type heat exchanger as illustrated in FIG. 1, or the so-calledserpentine type heat exchanger having a meandering heat exchanging tube.

[0206] [Third Embodiment]

[0207]FIG. 9 is a front view showing one side portion of a heatexchanger with a receiver-tank according to the third embodiment of thepresent invention. FIG. 10 is an enlarged cross-sectional view showing ablock flange and therearound of the heat exchanger. FIG. 11 is anenlarged cross-sectional view showing a block flange and therearound ofthe heat exchanger in a disassembled state.

[0208] As shown in these Figures, this heat exchanger is provided withthe so-called multi-flow type heat exchanger body 310, a receiver-tank303 and a block flange 304 for connecting the receiver-tank 303 to theheat exchanger body 310.

[0209] This heat exchanger 310 is provided with a pair of right and leftvertical headers 311 and 311 spaced apart from each other and aplurality of flat heat exchanging tubes 312 disposed horizontallybetween the headers 311 and 311 at certain intervals with both ends ofthereof being communicated with the corresponding headers 311 and 311. Acorrugated fin 313 is arranged on the outside of each outermost heatexchanging tube 312. Between the adjacent heat exchanging tubes 312 and312, corrugated fins 313 are arranged. A side plate 314 for protectingthe corrugated fin 313 is arranged on the outside of each outermost heatexchanging tube 312.

[0210] In the lower portion of each header 311 and 311, partitionmembers 316 b each for dividing the inside of the header are provided atthe same height. The upper side of the heat exchanger body 310 above thepartition members 316 b and 316 b and the lower side thereof below thepartition members 316 b and 316 b constitute a condensing portion C anda subcooling portion S, respectively.

[0211] In the condensing portion C, the aforementioned plurality oftubular elements 312 are divided into the first path Cl to the thirdpath C3 by partition members 316 a and 316 a provided in the headers 311and 311 at predetermined positions. In the subcooling portion S, theaforementioned plurality of tubular elements 312 are divided into thefourth path C4 to the fifth path C5 by partition members 316 a and 316 aprovided in the headers 311 and 311 at predetermined positions in thesame manner as in the first embodiment.

[0212] Furthermore, at the upper and lower end portions of the headers311 and 311 corresponding to the condensing portion C, a condensingportion inlet (not shown) and a condensing portion outlet 301 b areprovided, respectively. At the lower end portion of the left-hand header311 corresponding to the subcooling portion S, a subcooling portioninlet 302 a and a subcooling portion outlet 302 b are provided,respectively.

[0213] The gaseous refrigerant introduced into the condensing portioninlet (not shown) of the heat exchanger body 310 passes through thecondensing portion 301 in a meandering manner while exchanging heat withthe ambient air to be condensed, and flows out of the condensing portionoutlet 301 b of the left-hand header 311.

[0214] The liquefied refrigerant introduced from the subcooling portioninlet 302 a passes through the subcooling portion 302 in a meanderingmanner while exchanging heat with the ambient air to be subcooled, andflows out of the subcooling-portion outlet 302 b and the outlet pipe321.

[0215] The receiver-tank 303 has a vertically disposed cylindrical tankmain body 331 having a bottom wall constituted by an inlet-and-outletforming member 332. At an outer periphery of an upper portion of thetank main body 331, an outwardly protruded flange-shaped engagingprotrusion 331 a is formed (see FIG. 9).

[0216] As shown in FIGS. 10 and 12, the inlet-and-outlet forming member332 is provided with a downwardly protruded inlet convex stepped portion335 at the lower end thereof. This inlet convex stepped portion 335 hasa circular horizontal cross-sectional configuration having an axialcenter that coincides with the axial center of the receiver-tank 303.Furthermore, at the center of the lower surface of the inlet convexstepped portion 335, a downwardly protruded outlet convex steppedportion 336 is formed. This convex stepped portion 336 also has acircular horizontal cross-sectional configuration having an axial centerthat coincides with the axial center of the receiver-tank 303.

[0217] Furthermore, the inlet convex stepped portion 335 of theinlet-and-outlet forming member 332 is provided with four receiver-tankinlets 303 a so as to surround the outlet convex stepped portion 336 atpredetermined intervals. Each of the receiver-tank inlet 303 avertically penetrates the inlet-and-outlet forming member 332 to becommunicated with the inside of the tank main body 331.

[0218] Here, the total opening area of the four receiver-tank inlets 303a is formed such that the total opening area is larger than the openingarea of the receiver-tank outlet 303 b.

[0219] As shown in FIGS. 9 to 14, in the tank main body 331, arefrigerant suction pipe 330 is disposed vertically with the lower endthereof communicated with the inner end of the receiver tank outlet 303b. The upper end of the refrigerant suction pipe 330 is positionedsomewhat higher than the upper surface of the below-mentioned lowerdesiccant-filled-layer 351.

[0220] On the bottom of the tank main body 331, a lower perforated panel356 is disposed. In the lower inner space of the tank main body 331, apredetermined amount of desiccating spherical particle agents 305 suchas molecular sieves are filled to form a lower desiccant-filled-layer351 as a flow-resistance layer surrounding the refrigerant suction pipe330. On the upper surface of the desiccant-filled-layer 351, a middleperforated panel 357 is disposed via a filter 355.

[0221] Furthermore, above the lower desiccant-filled-layer 351 in thetank main body 331, an upper space 354 is formed. In the upper part ofthe upper space 354, an upper perforated panel 358 is fixed.

[0222] Above the upper perforated panel 358, a predetermined amount ofdesiccating spherical particle agents 305, such as molecular sieves, arefilled to form an upper desiccant-filled-layer 352 as desiccating-agentcharging members.

[0223] In this receiver-tank 303, the refrigerant introduced into thetank main body 331 via the inlet port 303 a goes up through the lowerdesiccant-filled-layer 351, and forms a liquid stagnation R in the upperspace 354. Only the liquefied refrigerant is inhaled from the upper endof the refrigerant suction pipe 330 and goes down through therefrigerant suction pipe 330 to be flowed out of the receiver-tankoutlet 303 b.

[0224] On the other hand, as shown in FIGS. 10 and 11, the block flange304 is integrally provided with a first block 341 to be arranged nearthe condensation portion outlet 301 b, a second block 343 to be arrangednear the subcooling portion inlet 302 a and a third block 343 to bearranged at the lower end of the receiver-tank 303. The side surface(joining surface) of the first block 341 is connected to the peripheryof the condensing portion outlet 301 b of the left-hand side header 311.On the other hand, the side surface (joining surface) of the secondblock 342 is connected to the periphery of the subcooling portion inlet302 a of the left-hand side header 311.

[0225] The upper surface of the third block 343 is positioned at thecorresponding height of the upper portion of the subcooling portion 302which is lower than a position of the condensing portion outlet 301 b.Formed on the upper surface of this third block 343 is an inlet concavestepped portion 345 having a circular horizontal cross-sectionalconfiguration into which the inlet convex stepped portion 335 of theaforementioned receiver-tank 303 can fit. Furthermore, at the bottom ofthe inlet concave stepped portion 345, an outlet concave stepped portion346 of a circular horizontal cross-sectional configuration into whichthe outlet convex stepped portion 336 of the receiver-tank 303 isformed.

[0226] The block flange 304 is provided with an inlet flow passage 304 afor connecting the condensing portion outlet 301 b with thereceiver-tank inlet 303 a and an outlet flow passage 304 b forconnecting the receiver-tank outlet 303 b with the subcooling portioninlet 302 a.

[0227] The inlet flow passage 304 a has an inlet side end portion whichopens to the joining surface of the first block 341 and is communicatedwith the condensing portion outlet 301 b, a middle portion which extendsdownwardly and an outlet side end portion which opens to the lower innerperiphery of the inlet concave stepped portion 345 of the third block343.

[0228] The outlet side opening of the aforementioned inlet flow passage304 a is positioned at the bottom portion of the inlet concave steppedportion 345. This position is lower than the portion of the condensingportion outlet 301 b, and equivalent to the upper portion of thesubcooling portion 302.

[0229] On the other hand, the inlet side opening of the outlet flowpassage 304 b is opened to the bottom surface of the third block 343,and the outlet side opening thereof is opened to the joining surface ofthe second block 342 and connected with the subcooling portion inlet 302a.

[0230] Tightly fitted into the inlet and outlet concave stepped portions345 and 346 of this block flange 304 are the inlet and outlet convexstepped portion 335 and 336 of the receiver-tank 303. Sealing rings 335a and 336 a such as O-rings are attached on a periphery of the convexstepped portions 335 and 336. Therefore, The sealing ring 336 a airtightly seals the gap between the inner surface of the outlet concavestepped portion 346 and the exterior surface of the outlet convexstepped portion 336. On the other hand, the sealing ring 335 a seals thegap between the innser surface of the inlet concave stepped portion 345and the external surface of convex step 335.

[0231] At the bottom portion of the inlet concave stepped portion 345, aclearance is formed between the bottom surface of the inlet concavestepped portion 345 and the lower end of the inlet port 303 a of thereceiver-tank 303 to thereby form a liquid-stagnating portion 340.

[0232] The upper portion of the receiver-tank 303 is attached to theleft-hand header 311 by a bracket 306. The bracket 306 has a bracket manbody 361 and a holding member 362.

[0233] As shown in FIGS. 15 to 17, the bracket main body 361 is providedwith an arc-shaped embracing portion 361 a which can be fitted on thehalf-periphery of the tank main body 331 of the receiver-tank 303. Atthe one end of this embracing portion 361 a, a joining portion 361 bwhich can fit on the external surface of the left-hand header 311 of theheat exchanger body 310 is provided.

[0234] Furthermore, at the end portion of the joining portion 361 b, anengaging stepped portion 361 c is formed. In the end surface of thejoining portion 361 b, a screw hole 361 d is formed. Furthermore, at theother end of the embracing portion 361 a, an axis-holding groove 361 eextending along the longitudinal direction of the receiver-tank 303 isformed. Furthermore, at the other end of the embracing portion 361 a anextended fixing member 361 f is formed. At the end portion of thisfixing member 361 f, an attaching-hole 361 g is formed.

[0235] The embracing portion 361 a of this bracket main body 361 isdisposed so as to embrace the rear half of the tank main body 331 at theposition above the flange-shaped engaging protrusion 331 a of the tankmain body 331 of the receiver-tank 303. In this state, the joiningportion 361 b is brazed to the external surface of the left-hand header311 of the heat exchanger body 310. Thus, the bracket main body 361 isfixed to the left-hand header 311.

[0236] On the other hand, the holding member 362 is provided with anarc-shaped embracing portion 362 a which can fit on the remaining halfperiphery of the tank main body 331. At one end of this embracingportion 362 a, an engaging protrusion 362 c which can engage with theengaging stepped portion 361 c of the aforementioned bracket main body361 is formed. Furthermore, as shown in FIGS. 9 and 15, an verticallyextended screw insertion slot 362 d which corresponds to the screw hole362 d of the bracket main body 361 is formed. Furthermore, at the otherend of the holding member 362, a vertically extended axis portion 362 ewhich can be inserted in the axis-holding groove 361 e of the bracketmain body 361 in a rotatable manner is provided.

[0237] The axis portion 362 e of this holding member 362 is insertedinto the axis-holding groove 361 e of the bracket main body 361 from oneend thereof. Thus, the covering member 362 is slidably attached to thebracket main body 361 in a rotatable manner about the axis-holdinggroove 361 e as a fulcrum. Then, the covering member 362 is rotatedabout the axis portion 362 e to fit on the front-half periphery of thetank main body 331. In this situation, a screw 365 is inserted in thescrew insertion slot 362 d and screws into the screw hole 361 d tothereby fix the covering member 362 to the bracket main body 361.

[0238] As shown in FIG. 9, the embracing portion 361 a and 362 a of thebracket 306 is engaged with the upper surface of the flange-shapedengaging protrusion 331 a of a tank main body 331 to thereby downwardlypress the tank main body 331.

[0239] The aforementioned heat exchanger with the receiver-tank is usedtogether with a compressor, a decompressing means and an evaporator as acondenser for use in an automobile air-conditioning refrigerationsystem. In this refrigeration cycle, the gaseous refrigerant of hightemperature and high pressure compressed by the compressor andintroduced from the condensing-portion inlet (not shown) passes throughthe condensing portion 301 while exchanging heat with the ambient air tobe condensed, and flows out of the condensing portion outlet 301 b.

[0240] The refrigerant flowed from the condensing portion outlet 301 bis introduced into an inlet concave stepped portion 345 through theinlet flow passage 304 a of the block flange 304, and forms liquidstagnation in the liquid-stagnating portion 340 of the bottom of theconcave stepped portion 345.

[0241] As shown in FIGS. 13 and 14, the liquefied refrigerant stagnatedin the liquid-stagnating portion 340 is introduced into the tank mainbody 331 through the receiver-tank inlet 303 a and spread horizontallyin a wide area, and then goes up through the lowerdesiccant-filled-layer 351 at a reduced speed. At the time of the risingof the refrigerant, since the lower desiccant-filled-layer 351 functionsas a resistance layer to the refrigeration flow, the upstream flowvelocity is reduced remarkably. The refrigerant passing through betweenthe particle-shaped desiccating agents 305 changes its directionfrequently to take a long course. Therefore, the flow velocity reducesremarkably and a local high velocity flow also disappears due to therectification function, resulting in an uniform upstream flow.

[0242] Thus, the liquefied refrigerant introduced into the upper space354 forms liquid-stagnation R without causing turbulence. On the otherhand, the flow velocity of the gas (gaseous refrigerant) introduced orgenerated in the liquefied refrigerant passing through the lowerdesiccant-filled-layer 305 is also abruptly reduced when the gaseousrefrigerant passes through the desiccant-filled-layer 351. Accordingly,when the gaseous refrigerant reaches the liquid-stagnation R, it calmlygoes up in the liquid-stagnation R and accumulates as a gaseousrefrigerant above the surface thereof without disturbing the surface.

[0243] Only the liquid refrigerant stably stagnated at the bottom amongthe liquid refrigerant forming the liquid-stagnation R flows into therefrigerant suction pipe 330, and then is introduced into the subcoolingzone 302 through the outlet flow passage 304 b of the block flange 304.

[0244] The liquefied refrigerant introduced in the subcooling portion302 passes through the subcooling portion 302 to be subcooled by theambient air, and then flows out of the subcooling-portion outlet 302band the outlet pipe 321. Thereafter, subcooled refrigerant passesthrough an evaporator and a compressor in this turn. Thus, therefrigerant circulates in the refrigeration cycle.

[0245] As mentioned above, in the heat exchanger with the receiver-tankaccording to this embodiment, the condensed refrigerant introduced intothe receiver-tank 303 forms the liquid-stagnation R quietly at a lowspeed, and bubbles will disappear smoothly and efficiently. Therefore,the stable range of amount of sealed refrigerant can be expanded, andonly the stable liquefied refrigerant can be extracted assuredly.Accordingly, since a stable supply of the liquefied refrigerant into thesubcooling portion 302 can be performed, a refrigeration cycle can beoperated stably and an outstanding refrigeration performance can beobtained.

[0246] Furthermore, since the stable supply of the liquefied refrigerantcan be attained because of the expanded stable range, a small and slimreceiver-tank 303 can be obtained and the performance can be improved,resulting in a small, lightweight and high-performance refrigerationsystem and in a reduced amount of refrigerant. In this embodiment, it ispreferable to satisfy the following condition: Ld<D, wherein “Ld” is theheight of the lower desiccant-filled-layer 351 and “D” is the innerdiameter of the tank main body 331.

[0247] That is, when the height Ld is too high, the liquid-stagnationstart position of the refrigerant becomes high. As a result, the stablerange starting point at the fewer sealed amount side of the refrigerantbecomes high, causing a narrow stable range. On the other hand, when theheight Ld is too low, the aforementioned resistance function and/orrectification function, etc. by the lower desiccant-filled-layer 351cannot fully be obtained, resulting in inadequate extraction of thestable liquefied refrigerant.

[0248] In this embodiment, since the desiccating agent 305 is dividedinto the lower desiccant-filled-layer 351 and the upperdesiccant-filled-layer 352, the predetermined amount of desiccatingagent 305 can be obtained assuredly. Therefore, the drying treatment ofthe refrigerant can be fully performed.

[0249] In this embodiment, it is preferable that the followingconditions are satisfied: 1.5φ≦L1≦0.8D, wherein the inner diameter ofthe tank main body 331, the distance between the center of thereceiver-tank inlet port 303 a and the center of the receiver-tankoutlet 303 b and the inner diameter of the inlet port 303 a of the tankmain body 331 are defined by D, LI and φ, respectively.

[0250] In this case, since the opening center of the receiver-tank inletport 303 a and the outlet center of the receiver-tank outlet 303 b aremoderately apart from each other, the upstream flow of the refrigerantintroduced from the receiver-tank inlet port 303 a will not beconcentrated on the center of the tank main body 331 (receiver-tankoutlet side), which further reduces the refrigerant flow velocity andfurther stabilizes the refrigerant surface. On the other hand, when thedistance L is too short or too long, the refrigerant introduced from thereceiver-tank inlet 303 a will concentrate on the center of the tankmain body 331, resulting in unstable extraction of the liquefiedrefrigerant.

[0251] Furthermore, in this embodiment, since the liquid-stagnatingportion 340 is formed at the outlet end of the inlet flow passage 304 ain the block flange 304, the refrigerant is once stored in theliquid-stagnating portion 340 and only the liquefied refrigerant isintroduced in the tank main body 331 through the receiver-tank inlet 303a. Accordingly, a mixing of the gaseous refrigerant into the tank mainbody 330 can be prevented more certainly, and the receiver-tank 330 canextract the liquefied refrigerant in more stabilized manner. Thisfurther enhances the refrigeration performance.

[0252] Furthermore, in this embodiment, since the opening area of thereceiver-tank inlet 303 a is formed larger than that of thereceiver-tank outlet 303 b, the flow velocity of the refrigerant can bereduced within the receiver-tank inlet 303 a and gas generation in therefrigerant can be prevented. Accordingly, bubble-extinguishing can befurther improved, resulting in a further enhanced refrigerationperformance.

[0253] In addition to the above, a plurality of receiver-tank inlets 303a are formed in the inlet-and-outlet forming member 332 disposed atpredetermined circumferential intervals. Therefore, the refrigerant canbe introduced into the tank main body 331 from the periphery of theinlet-and-outlet forming member 332 in an evenly distributed manner.Furthermore, it becomes possible to effectively prevent a generation ofbubbles due to the drift and/or turbulence of the refrigerant, resultingin a further enhanced refrigeration performance.

[0254] [Fourth Embodiment]

[0255]FIG. 18 is a schematic cross-sectional view showing areceiver-tank for refrigeration systems according to a fourth embodimentof the present invention. As shown in FIG. 18, in this receiver tank 303according to this embodiment, in place of the the upperdesiccant-filled-layer 352 shown in FIG. 13, a package-typedesiccating-agent-filled member 305 is disposed in the tank main body331 so that it floats in the liquid-stagnation R.

[0256] The package-type desiccating-agent-filled member 305 includes anet-bag member and particle-shaped desiccating agents filled in thenet-bag member. The other structures are the same as those of the thirdembodiment. According to the receiver tank 303 of this fourthembodiment, the same effects as mentioned above can be obtained.

[0257] [Fifth Embodiment]

[0258]FIG. 19 is a schematic cross-sectional view showing a lowerportion of a receiver-tank for refrigeration system according to a fifthembodiment of the present invention.

[0259] As shown in FIG. 19, in the receiver-tank 303 of this embodiment,the inlet opening portion (upper end) of the refrigerant suction pipe330 is formed to be an enlarged-diameter-portion 330 a in the shape of abell which opens upwardly. The upper level of theenlarged-diameter-portion 330 a is positioned at the same height as theupper surface of the perforated panel 357 arranged on the lowerdesiccant-filled-layer 351. The other structures are the same as thoseof the aforementioned embodiment.

[0260] According to the receiver-tank 303 of the fifth embodiment, thesame effects as mentioned above can be obtained. Furthermore, since theupper end portion of the enlarged-diameter-portion 330 a of therefrigerant suction pipe 330 is formed as a concave portion on the lowerdesiccant-filled-layer 351, the liquefied refrigerant easily flows intothe suction pipe 330 and the flow velocity in theenlarged-diameter-portion 330 a becomes slower than thenon-enlarged-diameter-portion of the suction pipe 330. Therefore, evenif a gaseous refrigerant is introduced into the suction pipe 330, thegaseous refrigerant escapes upwardly when the liquefied refrigerantpasses through the enlarged-diameter-portion 330 a, resulting in astable supply of the liquefied refrigerant.

[0261] In addition, it is not necessary to form theenlarged-diameter-portion 330 a of the refrigerant suction pipe 330 intoa bell-shaped configuration having a diameter gradually expanded. Forexample, as shown in FIG. 20A, the enlarged-diameter-portion 330 a mayhave a discontinuously expanded structure.

[0262] In order to effectively obtain the functions caused by theenlarged-diameter-portion 330 a of the refrigerant suction pipe 330, asshown in FIGS. 19 and 20A, it is recommended to satisfy the followingconditions: d1<d2≦3d1, and d1<h1≦5d1, wherein the inner diameter of thenon-enlarged-diameter-portion of the inlet of. the refrigerant suctionpipe 330, the maximum opening diameter of the enlarged-diameter-portion330 a and the depth of the enlarged-diameter-portion 330 a are definedby d1, d2 and h1, respectively.

[0263]FIG. 20B shows another modification. In this receiver-dryer 303, abubble-swallow-prevention wall 330 b of a cylindrical shape is formed atthe opening peripheral edge of the enlarged-diameter-portion 330 a ofthe refrigerant suction pipe 330.

[0264] According to this modification, bubbles of the gaseousrefrigerant going up through the liquid-stagnation R is hardly swallowedfrom the upper end of the refrigerant suction pipe 330, resulting in afurther steady supply of the liquefied refrigerant.

[0265] In order to effectively obtain the function of thebubble-swallow-prevention wall 330 b without causing any interruption ofthe liquefied refrigerant flow into the receiver-tank outlet 303 b, itis preferable that the following condition is satisfied: h2≦2d1, whereinthe inner diameter of the refrigerant suction pipe 303 and the height ofthe bubble-swallow-prevention wall 330 b are defined by d1 and h2,respectively.

[0266] In the aforementioned embodiment, although the present inventionis applied to a heat exchanger with a receiver-tank connected to a heatexchanger body having a subcooling portion, especially to the subcoolingsystem condenser, the present invention is not limited to the above. Thepresent invention can also be applied to a heat exchanger with areceiver tank connected to a heat exchanger body having no subcoolingportion, such as a condenser with a receiver-tank, as well as to areceiver-tank to be disposed separate to a heat exchanger.

EXAMPLES

[0267] A refrigeration system employing the heat exchanger with areceiver-tank shown in FIGS. 9 to 13 was prepared as an example X3. Arefrigeration system having the same structure as the above systemexcept for employing the receiver-tank shown in FIG. 2 was prepared asan example X1. Then, the relation between the subcooling-degree ° C. ofthe condensed refrigerant and the sealed amount g of the refrigerant wasmeasured by a charge examination. The results are shown in the graph ofFIG. 21.

[0268] As shown in this graph, as compared with the example X1, in theexample X3, the subcooling degree sharply goes up when the subcoolingdegree begins to go up, and reaches the stable range starting point(bubble extinguish point) at the side of fewer amount of sealedrefrigerants. Thus, it is understood that the stable range CA of theexample X3 is clearly larger than the stable range CB of the example X1.

[0269] Concretely, the bubble disappear point of the example X3 wasabout 970 g, and that of the example X1 was decreased by about 30 g ascompared with the bubble disappear point (about 1000 g) of the exampleX1.

[0270] In addition, in the refrigeration system employing thereceiver-tank of the fourth embodiment shown in FIG. 18, the same chargeexamination was performed. The result was the same as the aforementionedexample X3.

[0271] This application claims priority to Japanese Patent ApplicationNo. 2000-244199 filed on Aug. 11, 2000, the disclosure of which isincorporated by reference in its entirety.

[0272] The terms and expressions which have been employed herein areused as terms of description and not of limitation, and there is nointent, in the use of such terms and expressions, of excluding any ofthe equivalents of the features shown and described or portions thereof,but it is recognized that various modifications are possible within thescope of the invention claimed.

What is claimed is:
 1. A receiver-tank for use in a refrigeration cycle,wherein a condensed refrigerant is introduced into said receiver-tankand accumulated therein and only a liquefied refrigerant flows out ofsaid receiver-tank, said receiver-tank comprising: a tank main bodyhaving a refrigerant inlet and a refrigerant outlet each provided in abottom wall of said tank main body; a flow-resistance layer for reducinga flow velocity of a refrigerant passing through said flow-resistancelayer, said flow-resistance layer being provided in said tank main bodysuch that an upper space is formed above said flow-resistance layer; anda suction pipe provided in said tank main body, said suction pipe havingan upper end opened toward said upper space and a lower end communicatedwith said refrigerant outlet, whereby a refrigerant introduced into saidtank main body via said refrigerant inlet passes through saidflow-resistance layer upward to cause liquid stagnation of a liquefiedrefrigerant in said upper space, and the liquefied refrigerant flows outof said refrigerant outlet via said suction pipe.
 2. The receiver-tankfor use in a refrigeration cycle as recited in claim 1, wherein saidflow-resistance layer is provided with a plurality of dispersingpassages for dispersing the refrigerant in a radial and outwarddirection of said tank main body.
 3. The receiver-tank for use in arefrigeration cycle as recited in claim 1, wherein said flow-resistancelayer is a desiccant-filled-layer constituted by a plurality ofparticle-shaped desiccating agents.
 4. The receiver-tank for use in arefrigeration cycle as recited in claim 1, wherein a lower space fordiffusing the refrigerant introduced from said refrigerant inlet isformed under said flow-resistance-layer in said tank main body.
 5. Thereceiver-tank for use in a refrigeration cycle as recited in claim 4,wherein a height of said lower space is 25% or less of a thickness ofsaid flow-resistance layer.
 6. The receiver-tank for use in arefrigeration cycle as recited in claim 1, wherein said suction pipe hasan enlarged-diameter portion at an upper end thereof.
 7. Thereceiver-tank for use in a refrigeration cycle as recited in claim 6,wherein the following conditions are satisfied: d1<d2≦3d1, andd1<h1≦5d1, wherein an inner diameter of a non-enlarged-diameter portionof an intermediate portion of said suction pipe, the maximum openingdiameter of said enlarged-diameter portion and a depth of saidenlarged-diameter portion are defined by d1, d2 and h1, respectively. 8.The receiver-tank for use in a refrigeration cycle as recited in claim1, wherein an upwardly extended bubble-swallow-prevention wall is formedon a periphery of an upper end opening of said suction pipe.
 9. Thereceiver-tank for use in a refrigeration cycle as recited in claim 8,wherein the following conditions are satisfied: h2≦2d1, wherein an innerdiameter of a non-enlarged-diameter portion of an intermediate portionof said suction pipe and a height of said bubble-swallow-prevention wallare defined by d1 and h2, respectively.
 10. The receiver-tank for use ina refrigeration cycle as recited in claim 1, wherein the followingconditions are satisfied: 1.5φ≦L1≦0.8D, wherein a distance between acenter of said refrigerant outlet and a center of said refrigerantinlet, an inner diameter of said tank main body and an opening diameterof an outlet opening of said refrigerant inlet are defined by L1, D andφ, respectively.
 11. The receiver-tank for use in a refrigeration cycleas recited in claim 3, wherein the following conditions are satisfied:Ld≦0.7Le, wherein a thickness of said flow-resistance layer and aneffective length of said tank main body are defined by Ld and Le,respectively.
 12. The receiver-tank for use in a refrigeration cycle asrecited in claim 3, further comprising a filter layer disposed on atleast an upper surface of said desiccant-filled-layer.
 13. Thereceiver-tank for use in a refrigeration cycle as recited in claim 3,further comprising a pair of perforated plates disposed on upper andlower surfaces of said desiccant-filled-layer.
 14. The receiver-tank foruse in a refrigeration cycle as recited in claim 1, wherein saidrefrigerant outlet is formed at center of said bottom wall of said tankmain body, and wherein a plurality of said refrigerant inlets are formedaround said refrigerant outlet.
 15. The receiver-tank for use in arefrigeration cycle as recited in claim 14, wherein said plurality ofsaid refrigerant inlets are disposed at predetermined circumferentialintervals.
 16. A receiver-tank for use in a refrigeration cycle, whereina condensed refrigerant is introduced into said receiver-tank andaccumulated therein and only a liquefied refrigerant flows out of saidreceiver-tank, said receiver-tank comprising: a tank main body having arefrigerant inlet and a refrigerant outlet each provided in a bottomwall of said tank main body; a flow-resistance layer for reducing a flowvelocity of a refrigerant passing through said flow-resistance layer,said flow-resistance layer being provided in said tank main body suchthat an upper space is formed above said flow-resistance layer; asuction pipe provided in said tank main body, said suction pipe havingan upper end opened toward said upper space and a lower end communicatedwith said refrigerant outlet; and a desiccating-agent-filled memberdisposed in said upper space so as to space apart from saidflow-resistance layer, whereby a refrigerant introduced into said tankmain body via said refrigerant inlet passes through said flow-resistancelayer upward to cause liquid stagnation of a liquefied refrigerant insaid upper space, and the liquefied refrigerant flows out of saidrefrigerant outlet via said suction pipe.
 17. The receiver-tank for usein a refrigeration cycle as recited in claim 16, wherein saidflow-resistance layer is provided with a plurality of dispersingpassages for dispersing the refrigerant in a radial and outwarddirection of said tank main body.
 18. The receiver-tank for use in arefrigeration cycle as recited in claim 16, wherein said flow-resistancelayer is a desiccant-filled-layer constituted by particle-shapeddesiccating agents.
 19. The receiver-tank for use in a refrigerationcycle as recited in claim 16, wherein said desiccating-agent-filledmember is immovably disposed in said upper space.
 20. The receiver-tankfor use in a refrigeration cycle as recited in claim 16, wherein saiddesiccating-agent-filled member is movably disposed in said upper space.21. The receiver-tank for use in a refrigeration cycle as recited inclaim 18, wherein the following conditions are satisfied: Ld<D, whereina thickness of said desiccating-agent-filled member and an innerdiameter of said tank main body are defined by Ld and D, respectively.22. The receiver-tank for use in a refrigeration cycle as recited inclaim 16, wherein a lower space for diffusing the refrigerant introducedfrom said refrigerant inlet is formed under said flow-resistance-layerin said tank main body.
 23. The receiver-tank for use in a refrigerationcycle as recited in claim 16, wherein said refrigerant outlet is formedat a center of said bottom wall of said tank main body, and wherein aplurality of said refrigerant inlets are formed around said refrigerantoutlet.
 24. The receiver-tank for use in a refrigeration cycle asrecited in claim 23, wherein said plurality of said refrigerant inletsare disposed at predetermined circumferential intervals.
 25. A heatexchanger with a receiver-tank, comprising: a heat exchanger bodyincluding a pair of headers disposed in parallel at a certain distance,a plurality of heat exchanging tubes with both ends thereof connected tosaid pair of headers and a condensing portion outlet for discharging arefrigerant condensed while passing through said heat exchanging tubes;a receiver-tank having a receiver-tank inlet and a receiver-tank outleteach formed in a bottom wall of said receiver-tank, said receiver-tankaccumulating a refrigerant introduced from said receiver-tank inlet anddischarging only a liquefied refrigerant from said receiver-tank outlet;and a refrigerant passage for introducing the refrigerant flowed out ofsaid condensing portion outlet into said receiver-tank inlet, wherein aflow-resistance layer for reducing a flow velocity of a refrigerantpassing through said flow-resistance layer is provided in saidreceiver-tank such that an upper space is formed above saidflow-resistance layer, and wherein a suction pipe is provided in saidtank main body, said suction pipe having an upper end opened toward saidupper space and a lower end communicated with said receiver-tank outlet,whereby a refrigerant introduced into said tank main body via saidreceiver-tank inlet passes through said flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in said upper space,and the liquefied refrigerant flows out of said receiver-tank outlet viasaid suction pipe.
 26. The heat exchanger with a receiver-tank asrecited in claim 25, wherein said flow-resistance layer is adesiccant-filled-layer constituted by a plurality of particle-shapeddesiccating agents.
 27. The heat exchanger with a receiver-tank asrecited in claim 25, wherein a lower space for diffusing the refrigerantintroduced from said receiver-tank inlet is formed under saidflow-resistance-layer in said tank main body.
 28. A heat exchanger witha receiver-tank, comprising: a heat exchanger body including a pair ofheaders disposed in parallel at a certain distance, a plurality of heatexchanging tubes with both ends thereof connected to said pair ofheaders, partitioning members each partitioning an inside of said headerto thereby group said plurality of heat exchanging tubes into acondensing portion and a subcooling portion, a condensing portion outletfor discharging a refrigerant condensed while passing through said heatexchanging tubes and a subcooling portion inlet for introducing arefrigerant into said subcooling portion; a receiver-tank having areceiver-tank inlet and a receiver-tank outlet each formed in a bottomwall of said receiver-tank, said receiver-tank accumulating arefrigerant introduced from said receiver-tank inlet and dischargingonly a liquefied refrigerant from said receiver-tank outlet; and arefrigerant passage for introducing the refrigerant discharged from saidcondensing portion outlet into said receiver-tank inlet and introducingthe refrigerant discharged from said receiver-tank outlet into saidsubcooling portion inlet, wherein a flow-resistance layer for reducing aflow velocity of a refrigerant passing through said flow-resistancelayer is provided in said receiver-tank such that an upper space isformed above said flow-resistance layer, and wherein a suction pipe isprovided in said tank main body, said suction pipe having an upper endopened toward said upper space and a lower end communicated with saidreceiver-tank outlet, whereby a refrigerant introduced into said tankmain body via said receiver-tank inlet passes through saidflow-resistance layer upward to cause liquid stagnation of a liquefiedrefrigerant in said upper space, and the liquefied refrigerant flows outof said receiver-tank outlet via said suction pipe.
 29. The heatexchanger with a receiver-tank as recited in claim 28, wherein saidflow-resistance layer is a desiccant-filled-layer constituted by aplurality of particle-shaped desiccating agents.
 30. A heat exchangerwith a receiver-tank, comprising: a heat exchanger body including a pairof headers disposed in parallel at a certain distance, a plurality ofheat exchanging tubes with both ends thereof connected to said pair ofheaders and a condensing portion outlet for discharging a refrigerantcondensed while. passing through said heat exchanging tubes; areceiver-tank having a receiver-tank inlet and a receiver-tank outleteach formed in a bottom wall of said receiver-tank, said receiver-tankaccumulating a refrigerant introduced from said receiver-tank inlet anddischarging only a liquefied refrigerant from said receiver-tank outlet;and a refrigerant passage for introducing the refrigerant flowed out ofsaid condensing portion outlet into said receiver-tank inlet, wherein aflow-resistance layer for reducing a flow velocity of a refrigerantpassing through said flow-resistance layer is provided in saidreceiver-tank such that an upper space is formed above saidflow-resistance layer, wherein a suction pipe is provided in said tankmain body, said suction pipe having an upper end opened toward saidupper space and a lower end communicated with said receiver-tank outlet,and wherein a desiccating-agent-filled member is disposed in said upperspace so as to space apart from said flow-resistance layer, whereby arefrigerant introduced into said tank main body via said receiver-tankinlet passes through said flow-resistance layer upward to cause liquidstagnation of a liquefied refrigerant in said upper space, and theliquefied refrigerant flows out of said receiver-tank outlet via saidsuction pipe.
 31. The heat exchanger with a receiver-tank as recited inclaim 30, wherein said flow-resistance layer is a desiccant-filled-layerconstituted by a plurality of particle-shaped desiccating agents. 32.The heat exchanger with a receiver-tank as recited in claim 30, whereinsaid desiccating-agent-filled member is immovably disposed in said upperspace.
 33. The heat exchanger with a receiver-tank as recited in claim30, wherein said desiccating-agent-filled member is movably disposed insaid upper space.
 34. A heat exchanger with a receiver-tank, comprising:a heat exchanger body including a pair of headers disposed in parallelat a certain distance, a plurality of heat exchanging tubes with bothends thereof connected to said pair of headers, partitioning memberseach partitioning an inside of said header to thereby group saidplurality of heat exchanging tubes into a condensing portion and asubcooling portion, a condensing portion outlet for discharging arefrigerant condensed while passing through said heat exchanging tubesand a subcooling portion inlet for introducing the refrigerant into saidsubcooling portion; a receiver-tank having a receiver-tank inlet and areceiver-tank outlet each formed in a bottom wall of said receiver-tank,said receiver-tank accumulating a refrigerant introduced from saidreceiver-tank inlet and discharging only a liquefied refrigerant fromsaid receiver-tank outlet; and a refrigerant passage for introducing therefrigerant discharged from said condensing portion outlet into saidreceiver-tank inlet and introducing the refrigerant discharged from saidreceiver-tank outlet into said subcooling portion inlet, wherein aflow-resistance layer for reducing a flow velocity of a refrigerantpassing through said flow-resistance layer is provided in saidreceiver-tank such that an upper space is formed above saidflow-resistance layer, wherein a suction pipe is provided in said tankmain body, said suction pipe having an upper end opened toward saidupper space and a lower end communicated with said receiver-tank outlet,and wherein a desiccating-agent-filled member is disposed in said upperspace so as to space apart from said flow-resistance layer, whereby arefrigerant introduced into said tank main body via said receiver-tankinlet passes through said flow-resistance layer upward to cause liquidstagnation of a liquefied refrigerant in said upper space, and theliquefied refrigerant flows out of said receiver-tank outlet via saidsuction pipe.
 35. The heat exchanger with a receiver-tank as recited inclaim 34, wherein said flow-resistance layer is a desiccant-filled-layerconstituted by a plurality of particle-shaped desiccating agents.
 36. Acondensing apparatus for use in a refrigeration cycle, said condensingapparatus comprising: a condenser including a condensing portion forcondensing a refrigerant and a condensing portion outlet for dischargingthe refrigerant condensed by said condensing portion; a receiver-tankhaving a receiver-tank inlet and a receiver-tank outlet each formed in abottom wall of said receiver-tank, said receiver-tank accumulating arefrigerant introduced from said receiver-tank inlet and dischargingonly a liquefied refrigerant from said receiver-tank outlet; and arefrigerant passage for introducing the refrigerant flowed out of saidcondensing portion outlet into said receiver-tank inlet, wherein aflow-resistance layer for reducing a flow velocity of a refrigerantpassing through said flow-resistance layer is provided in saidreceiver-tank such that an upper space is formed above saidflow-resistance layer, and wherein a suction pipe is provided in saidtank main body, said suction pipe having an upper end opened toward saidupper space and a lower end communicated with said receiver-tank outlet,whereby a refrigerant introduced into said tank main body via saidreceiver-tank inlet passes through said flow-resistance layer upward tocause liquid stagnation of a liquefied refrigerant in said upper space,and the liquefied refrigerant flows out of said receiver-tank outlet viasaid suction pipe.
 37. The condensing apparatus for use in arefrigeration cycle as recited in claim 36, wherein said flow-resistancelayer is a desiccant-filled-layer constituted by a plurality ofparticle-shaped desiccating agents.
 38. A condensing apparatus for usein a refrigeration cycle, said condensing apparatus comprising: acondenser including a condensing portion for condensing a refrigerantand a condensing portion outlet for discharging the refrigerantcondensed by said condensing portion; a receiver-tank having areceiver-tank inlet and a receiver-tank outlet each formed in a bottomwall of said receiver-tank, said receiver-tank accumulating arefrigerant introduced from said receiver-tank inlet and dischargingonly a liquefied refrigerant from said receiver-tank outlet; and arefrigerant passage for introducing the refrigerant flowed out of saidcondensing portion outlet into said receiver-tank inlet, wherein aflow-resistance layer for reducing a flow velocity of a refrigerantpassing through said flow-resistance layer is provided in saidreceiver-tank such that an upper space is formed above saidflow-resistance layer, wherein a suction pipe provided in said tank mainbody, said suction pipe having an upper end opened toward said upperspace and a lower end communicated with said receiver-tank outlet, andwherein a desiccating-agent-filled member is disposed in said upperspace so as to space apart from said flow-resistance layer, whereby arefrigerant introduced into said tank main body via said receiver-tankinlet passes through said flow-resistance layer upward to cause liquidstagnation of a liquefied refrigerant in said upper space, and theliquefied refrigerant flows out of said receiver-tank outlet via saidsuction pipe.
 39. The condensing apparatus for use in a refrigerationcycle as recited in claim 38, wherein said flow-resistance layer is adesiccant-filled-layer constituted by a plurality of particle-shapeddesiccating agents.